An efficient Perkin synthesis of ¹³C‐labelled cinnamic acids from acetic acid as the source of the rare isotope

Abstract

This practitioner protocol describes an efficient Perkin synthesis of 1-13 C-palkylcinnamic acids from 1-13 C-acetic acid and the benzaldehyde with caesium carbonate and pivalic anhydride as reagents. Our new method employing the nonenolizable pivalic anhydride as the condensation agent avoids the minimum threefold excess of identically labelled carboxylate moieties (in both acid and anhydride) required in a conventional Perkin synthesis to prevent isotope dilution. More generally, this variation of the Perkin synthesis broadens the scope of that classic reaction to valuable carboxylic acid components.